The invention relates to a process for cooling an object by spraying a gas/liquid mixture in the form of a mist onto the surface of the object using at least one jetting nozzle and relates also to a device for carrying out the process.
Atomized air/water mixtures to cool extrusion billets have the advantage over water alone that there is a smaller risk of explosion with the former, this because the air/water mist striking the surface can be adjusted such that the water evaporates almost completely.
Known spraying systems are based on the principle of the Venturi pipe where the air/water mixture is already formed inside the jetting nozzle. Such Venturi nozzles have the disadvantage that the amount of air required to form a water mist is extremely great. Furthermore, the intensity of cooling at the area jetted by the mist varies locally to a very large degree, this because the region coinciding with the axis of the jet is cooled much stronger than the peripheral regions.